# -*- coding: utf-8 -*-
"""
Various methods of drawing scrolling plots.
"""

import pyqtgraph as pg
from pyqtgraph.Qt import QtCore, QtGui
import numpy as np
from PyQt5 import QtGui
import sys

app = QtGui.QApplication(sys.argv)

win = pg.GraphicsLayoutWidget()
win.setWindowTitle('pyqtgraph example: Scrolling Plots')



    

# 2) Allow data to accumulate. In these examples, the array doubles in length
#    whenever it is full. 
win.nextRow()
p3 = win.addPlot()
p4 = win.addPlot()
# Use automatic downsampling and clipping to reduce the drawing load
p3.setDownsampling(mode='peak')
p4.setDownsampling(mode='peak')
p3.setClipToView(True)
p4.setClipToView(True)
p3.setRange(xRange=[-200, 0])
p3.setLimits(xMax=0)
curve3 = p3.plot()
curve4 = p4.plot()

data3 = np.empty(200)
ptr3 = 0


def update1():
    global data3, ptr3
    data3[ptr3] = 5*np.sin(ptr3/5)+np.random.normal()
    ptr3 += 1
    if ptr3 >= data3.shape[0]:
        tmp = data3
        data3 = np.empty(data3.shape[0] * 2)
        data3[:tmp.shape[0]] = tmp
    curve3.setData(data3[:ptr3])
    curve3.setPos(-ptr3, 0)
    if ptr3 < 100:
            curve4.setData(data3[:ptr3])
    else:
        curve4.setData(data3[ptr3-100:ptr3])


timer = pg.QtCore.QTimer()
timer.timeout.connect(update1)
timer.start(50)

win.show()

## Start Qt event loop unless running in interactive mode or using pyside.
if __name__ == '__main__':
    import sys
    if (sys.flags.interactive != 1) or not hasattr(QtCore, 'PYQT_VERSION'):
        QtGui.QApplication.instance().exec_()